Call Your API Using the Client Credentials Flow

Auth0 makes it easy for your application to implement the Client Credentials Flow. Following successful authentication, the application will have access to an access token, which can be used to call your protected APIs. To learn more about access tokens, read Access Tokens.

Prerequisites

Before beginning this tutorial:

Steps

  1. Request tokens: From the authorized application, request an access token for your API.

  2. Call API: Use the retrieved access token to call your API.

Optional: Explore sample use cases

Request tokens

To access your API, you must request an access token for it. To do so, you will need to POST to the token URL.

Example POST to token URL




  


  
  
curl --request POST \
  --url 'https://{yourDomain}/oauth/token' \
  --header 'content-type: application/x-www-form-urlencoded' \
  --data grant_type=client_credentials \
  --data client_id=YOUR_CLIENT_ID \
  --data client_secret=YOUR_CLIENT_SECRET \
  --data audience=YOUR_API_IDENTIFIER
Was this helpful?
/
var client = new RestClient("https://{yourDomain}/oauth/token");
var request = new RestRequest(Method.POST);
request.AddHeader("content-type", "application/x-www-form-urlencoded");
request.AddParameter("application/x-www-form-urlencoded", "grant_type=client_credentials&client_id=YOUR_CLIENT_ID&client_secret=YOUR_CLIENT_SECRET&audience=YOUR_API_IDENTIFIER", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
Was this helpful?
/
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://{yourDomain}/oauth/token"

	payload := strings.NewReader("grant_type=client_credentials&client_id=YOUR_CLIENT_ID&client_secret=YOUR_CLIENT_SECRET&audience=YOUR_API_IDENTIFIER")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("content-type", "application/x-www-form-urlencoded")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
Was this helpful?
/
HttpResponse<String> response = Unirest.post("https://{yourDomain}/oauth/token")
  .header("content-type", "application/x-www-form-urlencoded")
  .body("grant_type=client_credentials&client_id=YOUR_CLIENT_ID&client_secret=YOUR_CLIENT_SECRET&audience=YOUR_API_IDENTIFIER")
  .asString();
Was this helpful?
/
var axios = require("axios").default;

var options = {
  method: 'POST',
  url: 'https://{yourDomain}/oauth/token',
  headers: {'content-type': 'application/x-www-form-urlencoded'},
  data: new URLSearchParams({
    grant_type: 'client_credentials',
    client_id: 'YOUR_CLIENT_ID',
    client_secret: 'YOUR_CLIENT_SECRET',
    audience: 'YOUR_API_IDENTIFIER'
  })
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});
Was this helpful?
/
#import <Foundation/Foundation.h>

NSDictionary *headers = @{ @"content-type": @"application/x-www-form-urlencoded" };

NSMutableData *postData = [[NSMutableData alloc] initWithData:[@"grant_type=client_credentials" dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[@"&client_id=YOUR_CLIENT_ID" dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[@"&client_secret=YOUR_CLIENT_SECRET" dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[@"&audience=YOUR_API_IDENTIFIER" dataUsingEncoding:NSUTF8StringEncoding]];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://{yourDomain}/oauth/token"]
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:10.0];
[request setHTTPMethod:@"POST"];
[request setAllHTTPHeaderFields:headers];
[request setHTTPBody:postData];

NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                if (error) {
                                                    NSLog(@"%@", error);
                                                } else {
                                                    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
                                                    NSLog(@"%@", httpResponse);
                                                }
                                            }];
[dataTask resume];
Was this helpful?
/
$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{yourDomain}/oauth/token",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "grant_type=client_credentials&client_id=YOUR_CLIENT_ID&client_secret=YOUR_CLIENT_SECRET&audience=YOUR_API_IDENTIFIER",
  CURLOPT_HTTPHEADER => [
    "content-type: application/x-www-form-urlencoded"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}
Was this helpful?
/
import http.client

conn = http.client.HTTPSConnection("")

payload = "grant_type=client_credentials&client_id=YOUR_CLIENT_ID&client_secret=YOUR_CLIENT_SECRET&audience=YOUR_API_IDENTIFIER"

headers = { 'content-type': "application/x-www-form-urlencoded" }

conn.request("POST", "/{yourDomain}/oauth/token", payload, headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))
Was this helpful?
/
require 'uri'
require 'net/http'
require 'openssl'

url = URI("https://{yourDomain}/oauth/token")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

request = Net::HTTP::Post.new(url)
request["content-type"] = 'application/x-www-form-urlencoded'
request.body = "grant_type=client_credentials&client_id=YOUR_CLIENT_ID&client_secret=YOUR_CLIENT_SECRET&audience=YOUR_API_IDENTIFIER"

response = http.request(request)
puts response.read_body
Was this helpful?
/
import Foundation

let headers = ["content-type": "application/x-www-form-urlencoded"]

let postData = NSMutableData(data: "grant_type=client_credentials".data(using: String.Encoding.utf8)!)
postData.append("&client_id=YOUR_CLIENT_ID".data(using: String.Encoding.utf8)!)
postData.append("&client_secret=YOUR_CLIENT_SECRET".data(using: String.Encoding.utf8)!)
postData.append("&audience=YOUR_API_IDENTIFIER".data(using: String.Encoding.utf8)!)

let request = NSMutableURLRequest(url: NSURL(string: "https://{yourDomain}/oauth/token")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
Was this helpful?
/



Parameters



Parameter Name
Description






grant_type
Set this to "client_credentials".




client_id
Your application's Client ID. You can find this value on the application's settings tab.




client_secret
Your application's Client Secret. You can find this value on the application's settings tab.  To learn more about available application authentication methods, read Application Credentials.




audience
The audience for the token, which is your API. You can find this in the Identifier field on your API's settings tab.




organization
Optional. The organization name or identifier you want the request to be associated with. To learn more, read Machine-to-Machine Access for Organizations.




Response
If all goes well, you'll receive an HTTP 200 response with a payload containing access_token, token_type, and expires_in values:
 

{
  "access_token":"eyJz93a...k4laUWw",
  "token_type":"Bearer",
  "expires_in":86400
}
Was this helpful?
/


Call API
To call your API from the M2M application, the application must pass the retrieved access token as a Bearer token in the Authorization header of your HTTP request.



  


  
  
curl --request GET \
  --url https://myapi.com/api \
  --header 'authorization: Bearer ACCESS_TOKEN' \
  --header 'content-type: application/json'
Was this helpful?
/
var client = new RestClient("https://myapi.com/api");
var request = new RestRequest(Method.GET);
request.AddHeader("content-type", "application/json");
request.AddHeader("authorization", "Bearer ACCESS_TOKEN");
IRestResponse response = client.Execute(request);
Was this helpful?
/
package main

import (
	"fmt"
	"net/http"
	"io/ioutil"
)

func main() {

	url := "https://myapi.com/api"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("content-type", "application/json")
	req.Header.Add("authorization", "Bearer ACCESS_TOKEN")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := ioutil.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
Was this helpful?
/
HttpResponse<String> response = Unirest.get("https://myapi.com/api")
  .header("content-type", "application/json")
  .header("authorization", "Bearer ACCESS_TOKEN")
  .asString();
Was this helpful?
/
var axios = require("axios").default;

var options = {
  method: 'GET',
  url: 'https://myapi.com/api',
  headers: {'content-type': 'application/json', authorization: 'Bearer ACCESS_TOKEN'}
};

axios.request(options).then(function (response) {
  console.log(response.data);
}).catch(function (error) {
  console.error(error);
});
Was this helpful?
/
#import <Foundation/Foundation.h>

NSDictionary *headers = @{ @"content-type": @"application/json",
                           @"authorization": @"Bearer ACCESS_TOKEN" };

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://myapi.com/api"]
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:10.0];
[request setHTTPMethod:@"GET"];
[request setAllHTTPHeaderFields:headers];

NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                if (error) {
                                                    NSLog(@"%@", error);
                                                } else {
                                                    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
                                                    NSLog(@"%@", httpResponse);
                                                }
                                            }];
[dataTask resume];
Was this helpful?
/
$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://myapi.com/api",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "authorization: Bearer ACCESS_TOKEN",
    "content-type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}
Was this helpful?
/
import http.client

conn = http.client.HTTPSConnection("myapi.com")

headers = {
    'content-type': "application/json",
    'authorization': "Bearer ACCESS_TOKEN"
    }

conn.request("GET", "/api", headers=headers)

res = conn.getresponse()
data = res.read()

print(data.decode("utf-8"))
Was this helpful?
/
require 'uri'
require 'net/http'
require 'openssl'

url = URI("https://myapi.com/api")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

request = Net::HTTP::Get.new(url)
request["content-type"] = 'application/json'
request["authorization"] = 'Bearer ACCESS_TOKEN'

response = http.request(request)
puts response.read_body
Was this helpful?
/
import Foundation

let headers = [
  "content-type": "application/json",
  "authorization": "Bearer ACCESS_TOKEN"
]

let request = NSMutableURLRequest(url: NSURL(string: "https://myapi.com/api")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
Was this helpful?
/



Sample use cases
Customize tokens
You can use Actions to deny access tokens based on custom logic and/or add claims to access tokens. Auth0 invokes Actions attached to the client credentials grant at runtime to execute your custom logic.
To learn more, read about the Actions Machine to Machine Flow.
View sample application: server client + API
For a sample implementation, read the Server Client + API architecture scenario. This series of tutorials is accompanied by a code sample that you can access in GitHub.
Once your API receives a request with an access token, it will need to validate the token. To learn more, read Validate Access Tokens.
Learn more